Production of craped or crimped artificial yarns



Jan. 12, 1937.

H. RADESTOCK 2,067,544 PRODUCTION OF CRAPED OR CRIMPED ARTIFICIAL YARNS Filed April 4, 1935 Patented Jan. 12, 1937 UNITED STATES PATENT OFFICE PRODUCTION OF CRAPED OR CRIMPED ARTIFICIAL YARNS many Application April 4, 1935, Serial No. 14,689 In Germany July 9, 1934 6 Claims.

Artificially produced fibres, for example artificial silk, staple fibres, are, as a rule, obtained in the manufacture as perfectly plain smooth threads. It is frequently desired for the further treatment, to provide the thread material with bends, waves, and the like, that is, to obtain a kind of craped or crinkled thread, either for obtaining particular effects in the weaving, knitting and the like, or to make the material, (as staple fibre) suitable for the production of yarns on cotton or wool spinning machines.

Hitherto, such crinkled threads have either been produced by subjecting the artificial thread material obtained to a special after-treatment process or it has been sought to impart a crinkling to the material in the spinning process itself by tensioning or piling together the thread bundles or by passing the bundles, for example before winding up, between fluted rollers.

These known processes do not, however, satisfy practical requirements. Apart from the processes themselves being mostly tedious and necessitating complicated and expensive special devices, the craping or cringling is mostly extremely uneven and, above all, unstable, since it disappears on the stretching, moistening, etc. of the thread.

It has been found that a good and stable thread craping can be attained in a very simple manner, if, during the spinning process, the thread drawn under normal or even increased tension from the nozzle, is wound up under rapid consecutive increasing and decreasing of the thread winding stretch, that is, the distance of the actuated winding-up device from the thread feed. These extensions and contractions of the winding stretch can be produced in a particularly simple manner by imparting, in the centrifugal spinning (can spinning process) to the guide funnel through which the thread is introduced into the spinning can, an eccentric position with respect to the axis of the spinning can. Since in this way the thread is not introduced centrally, that is, not at a point equi-distant towards all sides from the windingup device (can wall) but eccentrically to the spinning can, (that is, it leaves the thread feed at a point which is eccentric to the axial line) there takes place on its rotation a continuous alternation of the length of the winding-up stretch between a maximum and minimum distance with each half thread revolution, which is obviously the cause of the formation of the craping or crinkling places in the thread.

It is generally advisable for the point of introduction of the thread to be situated closer to the axial line of the spinning can than to the can wall. For example, with a spinning can of 150 mm. diameter, a distance amounting to 20 mm. of the point of introduction of the thread from the axis of the cam has been found very good. But 5 this depends entirely upon the crinkling desired, 50 that the point of introduction may, under certain circumstances, even lie closer to the wall of the can than to the axis.

A particularly uniform crinkling or crimping is 10 attained if the introducing member is gradually approached during the spinning more and more to the axial line of the spinning can, say in proportion to the increase in thickness of the cop. For example, with a can diameter of 150 mm. a 5 reduction of the distance of the point of introduction from the can axle line, from about 20 mm. to about 15 mm. has given very good results.

It has, furthermore, been found that the abso-' lute size of the stretch between the point of in- 15 troduction of the thread and the inner jacket surface of the spinning can or of the cop plays a definite role as to the nature of the crimping which is in any particular case attained. This means that the nature of the crimping is also 20 dependent upon the value chosen of the can diameter. Actually, there is obtained with a very small can diameter for example, mm. and less, a crimping consisting of extremely numerous small and sharply defined curves, whilst a spin- 25 ning can with a large diameter, for example 300 mm. and over, gives a crimping consisting of less numerous but larger curves. This holds good naturally under the assumption that the other conditions influencing the crimping remain sub- 30 stantially unaltered; for of course other factors play a part such for example as a change in the speed of the spinning can, towards giving an altered crimping, an increased speed effecting a correspondingly more frequent formation of turns 35 and thus a more pronounced crimping effect. One is thus able by a suitable selection of the size of the spinning can, to determine the nature of the crimping or respectively to adapt the size of the spinning can to the desired nature of the 40 crimping.

Otherwise, the carrying out of the process and the further treatment of the silk or the like corresponds entirely to the method of working in the usual can spinning process. Since the threads to 45 be crimped are fed to the spinning can in as plastic a condition as possible, that is, still not well fixed, (which can be attained in known manner by suitable composition and ripening of the viscose as also the adjustment of the acid con- 5 tent and temperature of the spinning bath) it may, as tests have shown, be advisable in order to obtain a particularly durable crimping, to treat the thread material before the further treatment, in an acid after-fixing bath, containing, for example, 5-7% H2804. It has also been found of great advantage for the crimping efiect to subject the fibre material in the further treatment to an intermediate drying directly after the washing.

The variations in the winding stretch rapidly following each other can also be produced in particular with spool, cylinder, reel and similar winding devices, by the rapid reciprocating movements (oscillations or vibrations) of the thread guide.

The accompanying drawing illustrates the invention by way of example.

In the accompanying drawing,

Figure 1 is in the nature of a diagram showing thespinning can in section, the guide funnel in elevation, and the course of the thread to the funnel is also illustrated.

Fig. 2 is a plan view of the can with several positions of the funnel indicated at I, II, III.

Fig. 3;, is a graph of variations in the winding distance; of. the thread.

Figure l diagrammatically shows the device used to carry out the new process. The thread coming from the spinning bath is guided over the guide roller e through the guide funnel d into the spinning can a mounted on the shaft b. The guide funnel d does not lie in the axis c: of the spinning. can. as in the case of the usual centrifugal spinning processes, but eccentrically with respect thereto. It is thereby brought about that during the rotation of the thread in the spinning can the winding distance (that is, the distance from the lower end i of the guide funnel d to the wall of the can) constantly varies between a minimum and. a maximum distance (i-g and ih).

This: variation in the length of the winding distance of the thread may be illustrated by means of a graph, for example by recording the period of one thread rotation (not one rotation of the can) or a number of thread rotations as an abscissa and the lengths of the winding distance as ordinates. The curves naturally produce quite a different diagram according to how far the point ofintroduction i is removed from the axis 0. If

the funnel lay in the axial line, the winding distance of the thread would be of constant length during one rotation of the thread and the diagram obtained would be in the form of a straight line parallel to the abscissa. If the point of introduction 1' lies near to the axis, quite flat curves are obtained, which become steeper as the distance of the point of introduction z from the axis increases, as is shown in Figure 3, in which the curves I, II and III correspond to the positions I, II and III of the feed funnel indicated in Figure 2. The constant variation of the length of the winding distance has the effect that the thread does not lie smooth and straight in the spun cake, but with characteristic turns and crinkles.

What I claim and desire to secure by Letters Patent of the United States is:

.1. Process for the production of craped artificial threads in a can-spinning machine which consists. in introducing the thread into the can at a point eccentric to the axis of the spinning can 2. Process for the production of craped artificial threads which consists in spinning the thread in a partially fixed condition, alternately increasing and decreasing the winding stretch, and. completing the fixing treatment after spinnmg.

3. Process for the production of craped artificial threads which consists in spinning the thread in a partially fixed plastic condition, alternately increasing and decreasing the winding stretch, drying the thread after spinning and subsequently subjecting the thread to treatment in an acid bath. a

4. Process for the production of craped artificial threads in a can-spinning machine which consists in introducing the thread into the can at a point eccentric to the axis of the spinning can and gradually approaching the point of introduction during the spinning toward the axial line of the spinning can.

5. Apparatus for the production of craped artificial threads comprising a spinning can and a thread feed member arranged eccentrically to the axis of rotation of said spinning can, whereby the winding stretch is alternately increased and decreased during rotation of the spinning can.

6. Apparatus according to claim 5 in which the threadfeed member'is movable towards said axis as the cop increases in thickness.

HANS RADESTOCK. 

